using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ServiceStack.Host;
using ServiceStack.Text;
using ServiceStack.Web;

namespace ServiceStack.NativeTypes.TypeScript;

public class TypeScriptGenerator : ILangGenerator
{
    public Lang Lang => Lang.TypeScript;
    public MetadataTypesConfig Config { get; }

    readonly NativeTypesFeature feature;
    public List<string> ConflictTypeNames = new();
    public List<MetadataType> AllTypes { get; set; }

    public TypeScriptGenerator(MetadataTypesConfig config)
    {
        Config = config;
        feature = HostContext.GetPlugin<NativeTypesFeature>();
    }
        
    public static bool UseUnionTypeEnums { get; set; }

    public static bool EmitPartialConstructors { get; set; } = true;

    public static Func<IRequest,string> AddHeader { get; set; }
    public static Action<StringBuilderWrapper, MetadataType> PreTypeFilter { get; set; }
    public static Action<StringBuilderWrapper, MetadataType> InnerTypeFilter { get; set; }
    public static Action<StringBuilderWrapper, MetadataType> PostTypeFilter { get; set; }
        
    public static Action<StringBuilderWrapper, MetadataPropertyType, MetadataType> PrePropertyFilter { get; set; }
    public static Action<StringBuilderWrapper, MetadataPropertyType, MetadataType> PostPropertyFilter { get; set; }
        
    public static List<string> DefaultImports = new() {
    };

    public static Dictionary<string, string> TypeAliases = new() {
        {"String", "string"},
        {"Boolean", "boolean"},
        {"DateTime", "string"},
        {"DateOnly", "string"},
        {"DateTimeOffset", "string"},
        {"TimeSpan", "string"},
        {"TimeOnly", "string"},
        {"Guid", "string"},
        {"Char", "string"},
        {"Byte", "number"},
        {"Int16", "number"},
        {"Int32", "number"},
        {"Int64", "number"},
        {"UInt16", "number"},
        {"UInt32", "number"},
        {"UInt64", "number"},
        {"Single", "number"},
        {"Double", "number"},
        {"Decimal", "number"},
        {"IntPtr", "number"},
        {"List", "Array"},
        {"Byte[]", "string"},
        {"Stream", "string"},
        {"HttpWebResponse", "Blob"},
        {"IDictionary", "any"},
        {"OrderedDictionary", "any"},
        {"Uri", "string"},
        {"Type", "string"},
    };

    public static Dictionary<string, string> ReturnTypeAliases = new() {
        {"Byte[]", "Blob"},
        {"Stream", "Blob"},
        {"HttpWebResponse", "Blob"},
    };
        
    private static string declaredEmptyString = "''";
    internal static readonly Dictionary<string, string> primitiveDefaultValues = new() {
        {"String", declaredEmptyString},
        {"string", declaredEmptyString},
        {"Boolean", "false"},
        {"boolean", "false"},
        {"DateTime", declaredEmptyString},
        {"DateTimeOffset", declaredEmptyString},
        {"TimeSpan", declaredEmptyString},
        {"Guid", declaredEmptyString},
        {"Char", declaredEmptyString},
        {"int", "0"},
        {"float", "0"},
        {"double", "0"},
        {"Byte", "0"},
        {"Int16", "0"},
        {"Int32", "0"},
        {"Int64", "0"},
        {"UInt16", "0"},
        {"UInt32", "0"},
        {"UInt64", "0"},
        {"Single", "0"},
        {"Double", "0"},
        {"Decimal", "0"},
        {"IntPtr", "0"},
        {"number", "0"},
        {"List", "[]"},
        {"Uint8Array", "new Uint8Array(0)"},
    };

    public HashSet<string> UseGenericDefinitionsFor { get; set; } = new()
    {
        typeof(QueryResponse<>).Name,
    };
        
    public static TypeFilterDelegate TypeFilter { get; set; }
    public static Func<string, string> CookedTypeFilter { get; set; }
    public static TypeFilterDelegate DeclarationTypeFilter { get; set; }
    public static Func<string, string> CookedDeclarationTypeFilter { get; set; }
    public static Func<string, string> ReturnMarkerFilter { get; set; }

    public static Func<List<MetadataType>, List<MetadataType>> FilterTypes { get; set; } = DefaultFilterTypes;

    public static List<MetadataType> DefaultFilterTypes(List<MetadataType> types) => types.OrderTypesByDeps();
        
    public static bool InsertTsNoCheck { get; set; }
        
    /// <summary>
    /// Add Code to top of generated code
    /// </summary>
    public static AddCodeDelegate InsertCodeFilter { get; set; }

    /// <summary>
    /// Add Code to bottom of generated code
    /// </summary>
    public static AddCodeDelegate AddCodeFilter { get; set; }

    /// <summary>
    /// Include Additional QueryString Params in Header Options
    /// </summary>
    public List<string> AddQueryParamOptions { get; set; }

    /// <summary>
    /// Emit code without Header Options
    /// </summary>
    public bool WithoutOptions { get; set; }

    public string DictionaryDeclaration { get; set; } = "export class Dictionary<T> { [Key: string]: T; }";
        
    public HashSet<string> AddedDeclarations { get; set; } = [];

    public static Func<TypeScriptGenerator, MetadataType, MetadataPropertyType, string> PropertyTypeFilter { get; set; }

    /// <summary>
    /// Whether property should be marked optional
    /// </summary>
    public static Func<TypeScriptGenerator, MetadataType, MetadataPropertyType, bool> IsPropertyOptional { get; set; } = DefaultIsPropertyOptional;
    public static bool DefaultIsPropertyOptional(TypeScriptGenerator generator, MetadataType type, MetadataPropertyType prop)
    {
        if (generator.Config.MakePropertiesOptional)
            return true;
        return !prop.IsRequired();
    }

    public void Init(MetadataTypes metadata)
    {
        var includeList = metadata.RemoveIgnoredTypes(Config);
        AllTypes = metadata.GetAllTypesOrdered();
        AllTypes.RemoveAll(x => x.IgnoreType(Config, includeList));
        AllTypes = FilterTypes(AllTypes);

        //TypeScript doesn't support reusing same type name with different generic airity
        var conflictPartialNames = AllTypes.Map(x => x.Name).Distinct()
            .GroupBy(g => g.LeftPart('`'))
            .Where(g => g.Count() > 1)
            .Select(g => g.Key)
            .ToList();

        this.ConflictTypeNames = AllTypes
            .Where(x => conflictPartialNames.Any(name => x.Name.StartsWith(name)))
            .Map(x => x.Name);
    }

    public MetadataType FindType(MetadataTypeName typeRef) =>
        typeRef == null ? null : FindType(typeRef.Name, typeRef.Namespace); 
    public MetadataType FindType(string name, string @namespace = null) => AllTypes.FirstOrDefault(x => x.Name == name 
        && (@namespace == null || @namespace == x.Namespace));

    public string GetCode(MetadataTypes metadata, IRequest request, INativeTypesMetadata nativeTypes)
    {
        var formatter = request.TryResolve<INativeTypesFormatter>();
        Init(metadata);

        List<string> defaultImports = new(!Config.DefaultImports.IsEmpty()
            ? Config.DefaultImports
            : DefaultImports);

        var globalNamespace = Config.GlobalNamespace;

        string defaultValue(string k) => request.QueryString[k].IsNullOrEmpty() ? "//" : "";

        var sbInner = StringBuilderCache.Allocate();
        var sb = new StringBuilderWrapper(sbInner);
        var includeOptions = !WithoutOptions && request.QueryString[nameof(WithoutOptions)] == null;
        if (includeOptions)
        {
            sb.AppendLine("/* Options:");
            sb.AppendLine("Date: {0}".Fmt(DateTime.Now.ToString("s").Replace("T", " ")));
            sb.AppendLine("Version: {0}".Fmt(Env.VersionString));
            sb.AppendLine("Tip: {0}".Fmt(HelpMessages.NativeTypesDtoOptionsTip.Fmt("//")));
            sb.AppendLine("BaseUrl: {0}".Fmt(Config.BaseUrl));
            sb.AppendLine();
            sb.AppendLine("{0}GlobalNamespace: {1}".Fmt(defaultValue("GlobalNamespace"), Config.GlobalNamespace));
            sb.AppendLine("{0}MakePropertiesOptional: {1}".Fmt(defaultValue("MakePropertiesOptional"), Config.MakePropertiesOptional));
            sb.AppendLine("{0}AddServiceStackTypes: {1}".Fmt(defaultValue("AddServiceStackTypes"), Config.AddServiceStackTypes));
            sb.AppendLine("{0}AddResponseStatus: {1}".Fmt(defaultValue("AddResponseStatus"), Config.AddResponseStatus));
            sb.AppendLine("{0}AddImplicitVersion: {1}".Fmt(defaultValue("AddImplicitVersion"), Config.AddImplicitVersion));
            sb.AppendLine("{0}AddDescriptionAsComments: {1}".Fmt(defaultValue("AddDescriptionAsComments"), Config.AddDescriptionAsComments));
            sb.AppendLine("{0}IncludeTypes: {1}".Fmt(defaultValue("IncludeTypes"), Config.IncludeTypes.Safe().ToArray().Join(",")));
            sb.AppendLine("{0}ExcludeTypes: {1}".Fmt(defaultValue("ExcludeTypes"), Config.ExcludeTypes.Safe().ToArray().Join(",")));
            sb.AppendLine("{0}DefaultImports: {1}".Fmt(defaultValue("DefaultImports"), defaultImports.Join(",")));
            AddQueryParamOptions.Each(name => sb.AppendLine($"{defaultValue(name)}{name}: {request.QueryString[name]}"));

            sb.AppendLine("*/");
            sb.AppendLine();
        }

        formatter?.AddHeader(sb, this, request);

        var header = AddHeader?.Invoke(request);
        if (!string.IsNullOrEmpty(header))
            sb.AppendLine(header);

        string lastNS = null;

        var existingTypes = new HashSet<string>();

        var requestTypes = metadata.Operations.Select(x => x.Request).ToSet();
        var requestTypesMap = metadata.Operations.ToSafeDictionary(x => x.Request);
        var responseTypes = metadata.Operations
            .Where(x => x.Response != null)
            .Select(x => x.Response).ToSet();

        foreach (var import in defaultImports)
        {
            var pos = import.IndexOf(':');
            sb.AppendLine(pos == -1
                ? $"import {import};"
                : $"import {{ {import.Substring(0, pos)} }} from \"{import.Substring(pos + 1).StripQuotes()}\";");
        }

        if (!string.IsNullOrEmpty(globalNamespace))
        {
            var moduleDef = Config.ExportAsTypes ? "export " : "declare ";
            sb.AppendLine();
            sb.AppendLine("{0}module {1}".Fmt(moduleDef, globalNamespace.SafeToken()));
            sb.AppendLine("{");

            sb = sb.Indent();
        }

        var insertCode = InsertCodeFilter?.Invoke(AllTypes, Config);
        if (insertCode != null)
            sb.AppendLine(insertCode);
            
        if (InsertTsNoCheck)
            sb.AppendLine("// @ts-nocheck");

        //ServiceStack core interfaces
        foreach (var type in AllTypes)
        {
            var fullTypeName = type.GetFullName();
            if (requestTypes.Contains(type))
            {
                if (!existingTypes.Contains(fullTypeName))
                {
                    MetadataType response = null;
                    if (requestTypesMap.TryGetValue(type, out var operation))
                    {
                        response = operation.Response;
                    }

                    lastNS = AppendType(ref sb, type, lastNS,
                        new CreateTypeOptions
                        {
                            Routes = metadata.Operations.GetRoutes(type),
                            ImplementsFn = () =>
                            {
                                if (!Config.AddReturnMarker
                                    && operation?.ReturnsVoid != true
                                    && operation?.ReturnType == null)
                                    return null;

                                if (operation?.ReturnsVoid == true)
                                    return nameof(IReturnVoid);
                                if (operation?.ReturnType != null)
                                    return Type("IReturn`1", new[] {
                                        ReturnTypeAliases.TryGetValue(operation.ReturnType.Name, out var returnTypeAlias)
                                            ? returnTypeAlias
                                            : Type(operation.ReturnType)
                                    });
                                return response != null
                                    ? Type("IReturn`1", new[] { Type(response.Name, response.GenericArgs) })
                                    : null;
                            },
                            IsRequest = true,
                            Op = operation,
                        });

                    existingTypes.Add(fullTypeName);
                }
            }
            else if (responseTypes.Contains(type))
            {
                if (!existingTypes.Contains(fullTypeName)
                    && !Config.IgnoreTypesInNamespaces.Contains(type.Namespace))
                {
                    lastNS = AppendType(ref sb, type, lastNS,
                        new CreateTypeOptions
                        {
                            IsResponse = true,
                        });

                    existingTypes.Add(fullTypeName);
                }
            }
            else if (AllTypes.Contains(type) && !existingTypes.Contains(fullTypeName))
            {
                lastNS = AppendType(ref sb, type, lastNS,
                    new CreateTypeOptions { IsType = true });

                existingTypes.Add(fullTypeName);
            }
        }

        var addCode = AddCodeFilter?.Invoke(AllTypes, Config);
        if (addCode != null)
            sb.AppendLine(addCode);

        if (!string.IsNullOrEmpty(globalNamespace))
        {
            sb = sb.UnIndent();
            sb.AppendLine();
            sb.AppendLine("}");
        }
            
        sb.AppendLine(); //tslint
        
        var ret = StringBuilderCache.ReturnAndFree(sbInner);
        return formatter != null ? formatter.Transform(ret, this, request) : ret;
    }

    private string AppendType(ref StringBuilderWrapper sb, MetadataType type, string lastNS,
        CreateTypeOptions options)
    {
        sb.AppendLine();
        AppendComments(sb, type.Description);
        if (options?.Routes != null)
        {
            AppendAttributes(sb, options.Routes.ConvertAll(x => x.ToMetadataAttribute()));
        }
        AppendAttributes(sb, type.Attributes);
        if (type.IsInterface != true) AppendDataContract(sb, type.DataContract);

        sb.Emit(type, Lang.TypeScript);
        PreTypeFilter?.Invoke(sb, type);

        if (type.IsEnum.GetValueOrDefault())
        {
            var isIntEnum = type.IsEnumInt.GetValueOrDefault() || type.EnumNames.IsEmpty(); 
            if ((isIntEnum || !UseUnionTypeEnums) && Config.ExportAsTypes)
            {
                var typeDeclaration = !Config.ExportAsTypes
                    ? "enum"
                    : "export enum";

                sb.AppendLine($"{typeDeclaration} {Type(type.Name, type.GenericArgs)}");
                sb.AppendLine("{");
                sb = sb.Indent();

                if (type.EnumNames != null)
                {
                    for (var i = 0; i < type.EnumNames.Count; i++)
                    {
                        var name = type.EnumNames[i];
                        var value = type.EnumValues?[i];

                        var memberValue = type.GetEnumMemberValue(i);
                        if (memberValue != null)
                        {
                            sb.AppendLine($"{name} = '{memberValue}',");
                            continue;
                        }

                        sb.AppendLine(value == null 
                            ? $"{name} = '{name}',"
                            : $"{name} = {value},");
                    }
                }

                sb = sb.UnIndent();
                sb.AppendLine("}");
            }
            else
            {
                var sbType = StringBuilderCache.Allocate();

                var typeDeclaration = !Config.ExportAsTypes
                    ? "type"
                    : "export type";

                sbType.Append($"{typeDeclaration} {Type(type.Name, type.GenericArgs)} = ");

                for (var i = 0; i < type.EnumNames.Count; i++)
                {
                    if (i > 0)
                        sbType.Append(" | ");

                    sbType.Append('"').Append(type.EnumNames[i]).Append('"');
                }

                sbType.Append(";");

                sb.AppendLine(StringBuilderCache.ReturnAndFree(sbType));
            }
        }
        else
        {
            var extends = new List<string>();

            //: BaseClass, Interfaces
            if (type.Inherits != null)
            {
                extends.Add(DeclarationType(type.Inherits.Name, type.Inherits.GenericArgs, out var addDeclaration));

                if (addDeclaration != null && !AddedDeclarations.Contains(addDeclaration))
                {
                    AddedDeclarations.Add(addDeclaration);
                    sb.AppendLine(addDeclaration);
                    sb.AppendLine();
                }
            }

            string responseTypeExpression = options?.Op != null
                ? "public createResponse() {}"
                : null;
            string responseMethod = options?.Op?.Method != null
                ? $"public getMethod() {{ return '{options.Op.Method}'; }}"
                : null;

            var interfaces = new List<string>();
            var implStr = options.ImplementsFn?.Invoke();
            if (!string.IsNullOrEmpty(implStr))
            {
                interfaces.Add(implStr);

                if (Config.ExportAsTypes)
                { 
                    if (implStr.StartsWith("IReturn<"))
                    {
                        var types = implStr.RightPart('<');
                        var returnType = types.Substring(0, types.Length - 1);

                        // This is to avoid invalid syntax such as "return new string()"
                        primitiveDefaultValues.TryGetValue(returnType, out var replaceReturnType);

                        if (returnType == "any")
                            replaceReturnType = "{}";
                        else if (returnType.EndsWith("[]"))
                            replaceReturnType = $"new Array<{returnType.Substring(0, returnType.Length -2)}>()";
                            
                        responseTypeExpression = replaceReturnType == null ?
                            "public createResponse() {{ return new {0}(); }}".Fmt(returnType) :
                            "public createResponse() {{ return {0}; }}".Fmt(replaceReturnType);
                    }
                    else if (implStr == "IReturnVoid")
                    {
                        responseTypeExpression = "public createResponse() {}";
                    }
                }
            }

            type.Implements.Each(x => interfaces.Add(Type(x)));

            var isClass = Config.ExportAsTypes && !type.IsInterface.GetValueOrDefault();
            var modifier = isClass ? "public " : "";
            var extend = extends.Count > 0
                ? " extends " + extends[0]
                : "";

            if (interfaces.Count > 0)
            {
                if (isClass)
                {
                    extend += " implements " + string.Join(", ", interfaces.ToArray());
                }
                else
                {
                    if (string.IsNullOrEmpty(extend))
                        extend = " extends ";
                    else
                        extend += ", ";

                    extend += string.Join(", ", interfaces.ToArray());
                }
            }

            var typeDeclaration = !Config.ExportAsTypes
                ? "interface"
                : $"export {(isClass ? "class" : "interface")}";

            var typeName = Type(type.Name, type.GenericArgs);
            sb.AppendLine($"{typeDeclaration} {typeName}{extend}");
            sb.AppendLine("{");

            sb = sb.Indent();
            InnerTypeFilter?.Invoke(sb, type);

            var addVersionInfo = Config.AddImplicitVersion != null && options.IsRequest;
            if (addVersionInfo)
            {
                sb.AppendLine(modifier + "{0}{1}: number; //{2}".Fmt(
                    GetPropertyName("Version"), isClass ? "" : "?", Config.AddImplicitVersion));
            }

            if (Config.ExportAsTypes)
            {
                if (type.Name == "IReturn`1")
                {
                    sb.AppendLine("createResponse(): T;");
                }
                else if (type.Name == "IReturnVoid")
                {
                    sb.AppendLine("createResponse(): void;");
                }
            }

            AddProperties(sb, type,
                includeResponseStatus: Config.AddResponseStatus && options.IsResponse
                                                                && type.Properties.Safe().All(x => x.Name != nameof(ResponseStatus)));

            if (EmitPartialConstructors && Config.ExportAsTypes && isClass)
            {
                sb.AppendLine();
                var callSuper = type.Inherits != null 
                    ? !(extend.StartsWith(" extends Array<") || extend.StartsWith(" extends Dictionary<"))
                        ? "super(init); " 
                        : "super(); "
                    : "";
                sb.AppendLine($"public constructor(init?: Partial<{typeName}>) {{ {callSuper}(Object as any).assign(this, init); }}");
            }

            if (Config.ExportAsTypes)
            {
                if (options?.Op != null)
                {
                    sb.AppendLine("public getTypeName() {{ return '{0}'; }}".Fmt(type.Name));
                }
                if (responseMethod != null)
                {
                    sb.AppendLine(responseMethod);
                }
                if (responseTypeExpression != null)
                {
                    sb.AppendLine(responseTypeExpression);
                }
            }

            sb = sb.UnIndent();
            sb.AppendLine("}");
        }

        PostTypeFilter?.Invoke(sb, type);
            
        return lastNS;
    }

    public virtual string GetPropertyType(MetadataPropertyType prop, out bool isNullable)
    {
        var propType = Type(prop.GetTypeName(Config, AllTypes), prop.GenericArgs);
        isNullable = propType.EndsWith("?");
        if (isNullable)
        {
            propType = propType.Substring(0, propType.Length - 1);
        }
        else
        {
            isNullable = prop.IsRequired != true;
        }
        return propType;
    }

    public void AddProperties(StringBuilderWrapper sb, MetadataType type, bool includeResponseStatus)
    {
        var wasAdded = false;
        var isClass = Config.ExportAsTypes && !type.IsInterface.GetValueOrDefault();
        var modifier = isClass ? "public " : "";

        var dataMemberIndex = 1;
        if (type.Properties != null)
        {
            foreach (var prop in type.Properties)
            {
                if (wasAdded) sb.AppendLine();

                var propType = GetPropertyType(prop, out var optionalProperty);
                propType = PropertyTypeFilter?.Invoke(this, type, prop) ?? propType;

                var optional = IsPropertyOptional(this, type, prop)
                    ? "?"
                    : "";

                wasAdded = AppendComments(sb, prop.Description);
                wasAdded = AppendDataMember(sb, prop.DataMember, dataMemberIndex++) || wasAdded;
                wasAdded = AppendAttributes(sb, prop.Attributes) || wasAdded;

                var initializer = (prop.IsRequired == true || Config.InitializeCollections) 
                                  && prop.IsEnumerable() && feature.ShouldInitializeCollection(type) && !prop.IsInterface()
                    ? prop.IsDictionary()
                        ? " = {}"
                        : " = []"
                    : "";
                
                sb.Emit(prop, Lang.TypeScript);
                PrePropertyFilter?.Invoke(sb, prop, type);
                sb.AppendLine(modifier + "{1}{2}: {0}{3};".Fmt(propType, GetPropertyName(prop), optional, initializer));
                PostPropertyFilter?.Invoke(sb, prop, type);
            }
        }

        if (includeResponseStatus)
        {
            if (wasAdded) sb.AppendLine();

            AppendDataMember(sb, null, dataMemberIndex++);
            sb.AppendLine(modifier + "{0}{1}: ResponseStatus;".Fmt(
                GetPropertyName(nameof(ResponseStatus)), Config.ExportAsTypes ? "" : "?"));
        }
    }

    public bool AppendAttributes(StringBuilderWrapper sb, List<MetadataAttribute> attributes)
    {
        if (attributes == null || attributes.Count == 0) return false;

        foreach (var attr in attributes)
        {
            if ((attr.Args == null || attr.Args.Count == 0)
                && (attr.ConstructorArgs == null || attr.ConstructorArgs.Count == 0))
            {
                sb.AppendLine("// @{0}()".Fmt(attr.Name));
            }
            else
            {
                var args = StringBuilderCacheAlt.Allocate();
                if (attr.ConstructorArgs != null)
                {
                    foreach (var ctorArg in attr.ConstructorArgs)
                    {
                        if (args.Length > 0)
                            args.Append(", ");
                        args.Append(TypeValue(ctorArg.Type, ctorArg.Value));
                    }
                }
                else if (attr.Args != null)
                {
                    foreach (var attrArg in attr.Args)
                    {
                        if (args.Length > 0)
                            args.Append(", ");
                        args.Append($"{attrArg.Name}={TypeValue(attrArg.Type, attrArg.Value)}");
                    }
                }
                sb.AppendLine("// @{0}({1})".Fmt(attr.Name, StringBuilderCacheAlt.ReturnAndFree(args)));
            }
        }

        return true;
    }

    public string TypeValue(string type, string value)
    {
        var alias = TypeAlias(type);
        if (value == null)
            return "null";
        if (alias == "string" || type == "String")
            return value.ToEscapedString();

        if (value.IsTypeValue())
        {
            //Only emit type as Namespaces are merged
            return "typeof(" + value.ExtractTypeName() + ")";
        }

        return value;
    }

    public static HashSet<string> ArrayTypes = new() {
        "List`1",
        "IEnumerable`1",
        "ICollection`1",
        "HashSet`1",
        "Queue`1",
        "Stack`1",
        "IEnumerable",
    };

    public static HashSet<string> DictionaryTypes = new() {
        "Dictionary`2",
        "IDictionary`2",
        "IOrderedDictionary`2",
        "OrderedDictionary",
        "StringDictionary",
        "IDictionary",
        "IOrderedDictionary",
    };

    public static HashSet<string> AllowedKeyTypes = new() {
        "string",
        "boolean",
        "number",
    };
        
    public string Type(MetadataTypeName typeName) => Type(typeName.Name, typeName.GenericArgs);

    public string DeclarationType(string type, string[] genericArgs, out string addDeclaration)
    {
        addDeclaration = null;
        var useType = DeclarationTypeFilter?.Invoke(type, genericArgs);
        if (useType != null)
            return useType;

        string cooked = null;

        if (genericArgs != null)
        {
            if (ArrayTypes.Contains(type))
            {
                cooked = "Array<{0}>".Fmt(GenericArg(genericArgs[0])).StripNullable();
            }
            if (DictionaryTypes.Contains(type))
            {
                addDeclaration = DictionaryDeclaration;
                cooked = "Dictionary<{0}>".Fmt(GenericArg(genericArgs[1])); //Key Type always string
            }
        }
            
        if (cooked == null)
            cooked = Type(type, genericArgs);
            
        useType = CookedDeclarationTypeFilter?.Invoke(cooked);
        if (useType != null)
            return useType;
            
        //TypeScript doesn't support short-hand Dictionary notation or has a Generic Dictionary Type
        if (cooked.StartsWith("{"))
            return "any";

        //TypeScript doesn't support short-hand T[] notation in extension list 
        //E.g. need to use `extends Array<Type>` instead of `extends Type[]`
        var arrParts = cooked.SplitOnFirst('[');
        return arrParts.Length > 1 
            ? "Array<{0}>".Fmt(arrParts[0]) 
            : cooked;
    }

    public string Type(string type, string[] genericArgs)
    {
        var useType = TypeFilter?.Invoke(type, genericArgs);
        if (useType != null)
            return useType;
            
        if (genericArgs != null)
        {
            string cooked = null;
            if (type == "Nullable`1")
                cooked = "{0}?".Fmt(GenericArg(genericArgs[0]));
            else if (type == "Nullable`1[]")
                cooked = GenericArg(genericArgs[0]) + "[]";
            else if (ArrayTypes.Contains(type))
                cooked = "{0}[]".Fmt(GenericArg(genericArgs[0])).StripNullable();
            else if (DictionaryTypes.Contains(type))
            {
                var keyArg = GenericArg(genericArgs[0]);
                var valArg = genericArgs[1];
                var keyType = GetKeyType(keyArg);
                var valType = GenericArg(valArg); 
                cooked = "{ [index:" + keyType + "]: " + valType + "; }";
            }
            else
            {
                var parts = type.Split('`');
                if (parts.Length > 1)
                {
                    var args = StringBuilderCacheAlt.Allocate();
                    foreach (var arg in genericArgs)
                    {
                        if (args.Length > 0)
                            args.Append(", ");

                        if (arg.StartsWith("{") || arg.Contains("<{")) // { [name:T]: T }
                            args.Append(arg);
                        else
                            args.Append(GenericArg(arg));
                    }
                    var genericArgsList = StringBuilderCacheAlt.ReturnAndFree(args);

                    var typeName = TypeAlias(type);
                    var suffix = "";
                    if (typeName.EndsWith("[]"))
                    {
                        suffix = "[]";
                        typeName = typeName.Substring(0, typeName.Length - 2);
                    }

                    cooked = $"{typeName}<{genericArgsList}>{suffix}";
                }
            }

            if (cooked != null)
                return CookedTypeFilter?.Invoke(cooked) ?? cooked;
        }
        else
        {
            type = type.StripNullable();
        }

        return TypeAlias(type);
    }

    private string TypeAlias(string type)
    {
        type = type.SanitizeType();
        if (type == "Byte[]")
            return TypeAliases["Byte[]"];

        var arrParts = type.SplitOnFirst('[');
        if (arrParts.Length > 1)
        {
            var numberOfDimensions = type.Count(c => c == '[');
            var arrayDimensions = String.Concat(Enumerable.Range(0, numberOfDimensions).Select(_ => "[]"));
                
            return "{0}{1}".Fmt(TypeAlias(arrParts[0]), arrayDimensions);
        }

        TypeAliases.TryGetValue(type, out var typeAlias);

        var cooked = typeAlias ?? NameOnly(type);
        return CookedTypeFilter?.Invoke(cooked) ?? cooked;
    }

    public string NameOnly(string type)
    {
        var name = ConflictTypeNames.Contains(type)
            ? type.Replace('`','_')
            : type.LeftPart('`');

        return name.LastRightPart('.').SafeToken();
    }

    public bool AppendComments(StringBuilderWrapper sb, string desc)
    {
        if (desc != null && Config.AddDescriptionAsComments)
        {
            sb.AppendLine("/** @description {0}".Fmt(desc.SafeComment()) + " */");
        }
        return false;
    }

    public void AppendDataContract(StringBuilderWrapper sb, MetadataDataContract dcMeta)
    {
        if (dcMeta == null)
        {
            if (Config.AddDataContractAttributes)
                sb.AppendLine("// @DataContract()");
            return;
        }

        var dcArgs = "";
        if (dcMeta.Name != null || dcMeta.Namespace != null)
        {
            if (dcMeta.Name != null)
                dcArgs = "Name={0}".Fmt(dcMeta.Name.QuotedSafeValue());

            if (dcMeta.Namespace != null)
            {
                if (dcArgs.Length > 0)
                    dcArgs += ", ";

                dcArgs += "Namespace={0}".Fmt(dcMeta.Namespace.QuotedSafeValue());
            }

            dcArgs = "({0})".Fmt(dcArgs);
        }
        sb.AppendLine("// @DataContract{0}".Fmt(dcArgs));
    }

    public bool AppendDataMember(StringBuilderWrapper sb, MetadataDataMember dmMeta, int dataMemberIndex)
    {
        if (dmMeta == null)
        {
            if (Config.AddDataContractAttributes)
            {
                sb.AppendLine(Config.AddIndexesToDataMembers
                    ? "// @DataMember(Order={0})".Fmt(dataMemberIndex)
                    : "// @DataMember()");
                return true;
            }
            return false;
        }

        var dmArgs = "";
        if (dmMeta.Name != null
            || dmMeta.Order != null
            || dmMeta.IsRequired != null
            || dmMeta.EmitDefaultValue != null
            || Config.AddIndexesToDataMembers)
        {
            if (dmMeta.Name != null)
                dmArgs = "Name={0}".Fmt(dmMeta.Name.QuotedSafeValue());

            if (dmMeta.Order != null || Config.AddIndexesToDataMembers)
            {
                if (dmArgs.Length > 0)
                    dmArgs += ", ";

                dmArgs += "Order={0}".Fmt(dmMeta.Order ?? dataMemberIndex);
            }

            if (dmMeta.IsRequired != null)
            {
                if (dmArgs.Length > 0)
                    dmArgs += ", ";

                dmArgs += "IsRequired={0}".Fmt(dmMeta.IsRequired.ToString().ToLower());
            }

            if (dmMeta.EmitDefaultValue != null)
            {
                if (dmArgs.Length > 0)
                    dmArgs += ", ";

                dmArgs += "EmitDefaultValue={0}".Fmt(dmMeta.EmitDefaultValue.ToString().ToLower());
            }

            dmArgs = "({0})".Fmt(dmArgs);
        }
        sb.AppendLine("// @DataMember{0}".Fmt(dmArgs));

        return true;
    }

    public string GenericArg(string arg)
    {
        return ConvertFromCSharp(arg.TrimStart('\'').ParseTypeIntoNodes());
    }

    public string ConvertFromCSharp(TextNode node)
    {
        var sb = new StringBuilder();

        if (node.Text == "Nullable")
            return TypeAlias(node.Children[0].Text);

        if (node.Text == "List")
        {
            sb.Append(ConvertFromCSharp(node.Children[0]));
            sb.Append("[]");
        }
        else if (node.Text == "List`1")
        {
            var type = node.Children.Count > 0 ? node.Children[0].Text : "any";
            sb.Append(type).Append("[]");
        }
        else if (node.Text == "Dictionary")
        {
            sb.Append("{ [index:");
            var keyType = ConvertFromCSharp(node.Children[0]);
            sb.Append(GetKeyType(keyType));
            sb.Append("]: ");
            sb.Append(ConvertFromCSharp(node.Children[1]));
            sb.Append("; }");
        }
        else
        {
            if (node.Text == "Tuple")
                node.Text += "`" + node.Children.Count;

            sb.Append(TypeAlias(node.Text));
            if (node.Children.Count > 0)
            {
                sb.Append("<");
                for (var i = 0; i < node.Children.Count; i++)
                {
                    var childNode = node.Children[i];

                    if (i > 0)
                        sb.Append(",");

                    sb.Append(ConvertFromCSharp(childNode));
                }
                sb.Append(">");
            }
        }

        return sb.ToString();
    }

    private static string GetKeyType(string keyType)
    {
        var jsKeyType = AllowedKeyTypes.Contains(keyType)
            ? keyType
            : "string";
        return jsKeyType;
    }

    public string GetPropertyName(string name) => name.SafeToken().PropertyStyle(); 
    public string GetPropertyName(MetadataPropertyType prop) => 
        prop.GetSerializedAlias() ?? prop.Name.SafeToken().PropertyStyle();
}

public static class TypeScriptGeneratorExtensions
{
    public static string InReturnMarker(this string type)
    {
        var useType = TypeScriptGenerator.ReturnMarkerFilter?.Invoke(type);
        if (useType != null)
            return useType;
            
        if (type.StartsWith("{"))
            return "any";

        var pos = type.IndexOf("<{", StringComparison.Ordinal);
        if (pos >= 0)
        {
            var ret = type.LeftPart("<{") + "<any>" + type.LastRightPart("}>");
            return ret;
        }
            
        //Note: can only implement using Array short-hand notation: IReturn<Type[]>

        return type;
    }
        
    public static string PropertyStyle(this string name)
    {
        return JsConfig.TextCase == TextCase.CamelCase
            ? name.ToCamelCase()
            : JsConfig.TextCase == TextCase.SnakeCase
                ? name.ToLowercaseUnderscore()
                : name;
    }
}